Among drugs currently used in drug therapy for depression and panic disorder, fluvoxamine maleate (1991) and paroxetine hydrochloride (2000) were developed as selective serotonin reuptake inhibitors (SSRI). SSRI is a first-line drug for both acute treatment and long-term treatment of depression and panic disorder. However, SSRI has some issues such as drug effects appearing only through chronic administration, drug withdrawal because of adverse effects, and side effects including withdrawal signs and influence on cognitive functions. Therefore, there is a strong demand for development of effective drugs having an immediate activity and fewer side effects.
One of factors involved with ageing is oxidative stress. Antioxidative substances reportedly have antiaging activity. For example, oolong tea containing antioxidants is considered to have antiaging activity (Biol Pharm Bull Vol 26 No 5 739-742 2003). On the other hand, while deprenyl reportedly increases the survival rate and is used as a monoamine oxidase B inhibitor in treatment for Parkinson's disease, this has been confirmed to be due to its antioxidant activity (Mech Ageing Dev Vol 46 No 1-3 237-262 1988). However, these substances do not offer antiaging activity and increase in the survival rate of animals at satisfactory levels.
Edaravone is a free radical scavenger having antioxidative activity and used as a neuroprotectant. However, it is not highly effective and various side effects including kidney failure have been reported (The Japan Stroke Society:Clinical Guidline for Stroke (2004), 42-43).
Curcumin is a component of Curcuma longa contained in curry in a large amount and has antiinflammatory and antioxidative activity equivalent to prescribed nonsteroidal antiinflammatory drugs (NSAIDs). Studies have shown that curcumin inhibits amyloid-related pathologies (Pharmacia, Japanese Pharmacology Association, Vol. 38, No. 9, 891-892, 2002). However, curcumin does not inhibit amyloid deposition at satisfactory levels.
Booklet of International Publication No. 01/009131 and Booklet of International Publication No. 2002/060907 disclose brain function improvers containing heterocyclic compounds having specific structures. The heterocyclic compounds are disclosed as brain function improvers leading to treatment for memory loss and memory acquisition/retention disorder in senile dementia, Alzheimer's disease and related disorders. Other effects useful as antidepressant, neuroprotectant, amyloid β inhibitor, and age retardant are not disclosed.